In a conventional system for secure transport of customer data, as shown in FIG. 1, data of a client is encrypted by an encryption device of the client, and then is transported by an optical transport network (OTN) transport device to an OTN transport device of another client through a fiber network, and a decryption device of the another client sends the received encrypted data to the another client after decrypting the received encrypted data. Therefore, for conventional data transmission, different encryption devices need to be configured according to different types of customer services, and costs of constructing a secure transport system are high.